There is no shortage of videos of how that quick jolt of electricity fails. Here are some examples: https://youtu.be/LQRAfJyEsko?t=979

Note, that those slaughterhouse are usually on smaller scales, than what is considered factory-farming. Slaughtering is just a small part of the suffering anyways and cruelty does not strictly depend on scale. Where I’m from, southern Germany, last time I looked, half of the milk farmers tether their cows, affecting a quarter of the cows in that region. Those are your neighbourhood family-owned farms.

The easiest way to not support any of that cruelty to animals, is to avoid animal based products.

Your hypothesis does not hold for a large amount of people. There’s a non-negligible chance, that it would not be true for yourself, IF you did not eat meat for ethical reasons.